Relay



Jan. 18, 1944. H. a BucKLEN, JR 2,339,675

RELAY Filed latch 9, 1942 y 3 Sheets-Sheet 1 Jan 18, 1944 H. E. BUCKLEN,JR 2,339,576

- A RELAY Filed March 9, 1942 3 Sheets-Sheet 2 MIM/g Jam 18, 1944 H. E.BUCKLN, JR 2,339,676

RELAY A Filed March 9, 1.942 s sheets-sheet s 4Patented Jan. 18, 1944UNITED STATES PATENT GFFICE 17 Claims.

This invention relates to relays, and more particularly is concernedwith relays useful in aviation where high altitudes are encountered atlow atmospheric pressures, and where quick turns and drops causeseparation of the normal relay contacts. The invention is alsoapplicable to relays of the high cycling type where rapid making andbreaking of the circuit causes correspending rapid deterioration of thecontacts and requires frequent replacement.

The invention also contemplates, within its general premises, the use ofan enclosed type relay or an open contact type relay, the particulartype beingdependent upon the service to which it is subjected.

Broadly speaking, the present invention is based upon the use of a relayhaving contact arrangements which prevent corrosion or oxidation of thecontacts, and which eliminates to a large extent the arcing andconsequent pitting of such contacts or overheating thereof, and is animprovement and modification of the invention shown and described in thecopending application of H. E. Bucklen, et al., Serial No, 384,542,filed March 21, 1941.

The invention further contemplates the use of both liquid and gas cooledcontacts, and the use of a uid around and adjacent the contacts whichwill provide lubrication cooling and resultant reduction ofdeterioration of such contact.

In considering the broad aspects of the present invention, considerationmust rst be given to the fact that the arcing between a pair of contactsis a direct function under given current conditions of the gap betweenthe contacts and the medium therebetween, whether it be air or someother form of gas. For example, under similar conditions of temperatureand pressure, I have found that, while only 1.4 amperes can be safelycarried through a relay of predetermined design in open air, if thisrelay is placed in a hydrogen atmosphere, approximately 100 amperes canbe so carried without arcing. This is of extreme importance when it isconsidered that relays for aviation work must operate both at sea levelpressures and at 40,000 feet altitude. At such a high altitude, theatmospheric pressure is reduced to approximately of the pressure at sealevel. The duration of an electrical arc when interrupted between tworelay contacts has been found to be six times longer at one-halfatmospheric pressure than at normal atmospheric pressure. In addition,if a relay is enclosed under normal atmospheric pressure when iiown toan altitude of 40,000 feet, the temperature drops to such a point thatthe air pressure may be reduced to three-fourths atmospheric. Theduration of the arc would then be almost three times longer than atnormal sea level. The law governing this states that the sparkingpotential of a gas is a function only of the product of the openingbetween the relay contacts and the pressure of the gas, or, in otherwords, of the mass of gas between the electrodes.

Thus, it is obvious that a relay with open contacts would be quicklydestroyed in operation at high altitudes. The best gas for short areduration and maximum interrupting ability appears to be hydrogen at thehighest possible pressure, since nitrogen has been found to besubstantially similar to air.

Also, in aviation work, the relay cannot be of the gravity operatedtype, inasmuch as the instrument must be capable of operation in anyposition. Thus, mercury relays do not lend themselves readily to thisuse. Glass enclosed mechanical relays are too fragile for the servicewhich is encountered in aviation. Furthermore, such envelopes of glasscannot be sealed off with a pressure higher than three-fourthsatmosphere due to the fact that the heat from the sealing torch expandsthe gas within the envelope. As a consequence, most glass tubes of thistype are sealed oiT at a pressure of nine pounds per square inch, ascompared with the normal atmospheric pressure of 14.2 pounds. Ittherefore appears, and my developments have led me to the conclusion,that the solution of this problem is to use relay mechanisms of themechanical open contact type, and enclose and seal them within a metalenvelope which is designed to stand a high pressure of hydrogen gas.Hydrogen gas is very superior to practically any other gas due partly tothe fact that it has the ability to absorb about seven times more heatthan the corresponding amount of air, and also apparently is many timesmore effective so far as maximum interruption currents are concerned inopen contact type relays.

Therefore, the present invention contemplates as one of its objects, theprovision of an enclosed type relay for aviation use consisting of amechanical relay; i. e., the normal open contact type enclosed within ametal envelope, which is so arranged that it can be sealed against theentrance or exit of gases. This seal can be of the type shown in theBear Patent No. 2,251,011, issued July 29, 1941, in which the end of theenvelope is crimped over to form a locking joint, or the seal can be ofthe screw end type suitably arranged for pressure. The relay placedwithin this envelope is surrounded by hydrogen gas, preferably under apressure of 4 to 6 atmospheres, the envelope and the relay having firstbeen subjected to a hydrogen annealing process such as shown in Hedinapplication, Serial No. 325,154, filed March 21, 1940, now Patent No.2,284,899, issued June 2, 1942. This provides a relay having highresistance against arcing, and which is capable of operation regardlessof the surrounding pressure of the atmosphere. Furthermore, the relay isfully protected by the metal envelope against damage and is springoperated rather than gravity operated.

In conjunction with the use of such an enclosed structure, I preferablyalso provide an improved type of seal for a hydrogen filled envelope. Ihave found that in place of ordinary pure rubber as a gasketingmaterial, the use of synthetic rubber, such as thiokol or neoprene,which has been treated with polyvinyl alcohol to close the poresthereof, provides a synthetic flexible sealing means, which isapproximately ten times more resistant to the passage of hydrogen gasthan the former pure rubber gaskets. The relay structure itself isfirmly anchored to a suitable insulating member carried in the envelope,and is rigidly held in position to take the jars and shocks encounteredin aviation work without in anywise affecting the operatingcharacteristics of the relay.

In connection with the use of rubber gaskets as seals, I have also foundthat by dipping these gaskets in a wax, such as a wax knowncornmercially as Johnsons Liquid Wax, #RG-101, or the equivalent, andthen baking the gasket at 200 to 250 degrees Fahrenheit, the pores ofthe gaskets may be sealed closed to prevent any possibility of hydrogenescaping from the interior of the switch envelope.

With such gasket means as described above, the relay envelope may beprovided with a screw threaded cap to allow for taking apart of theassembly for servicing or inspection if so desired.

'I'he present invention also contemplates, in addition to the envelope,hydrogen gas and relay structure combination just described, the use ofa synthetic liquid which has distinct advantages insofar as maintainingthe contacts in proper condition. This synthetic liquid, I have foundfrom long research and experiment, should be an anhydrous, alkalineliquid capable of absorbing moisture if any is present, and havingcertain characteristics of viscosity which render it extremely valuablein this use. Such a liquid is triethanolamine. This liquid hasrelatively low viscosity which gives it a viscous lubrication quality,allowing it to adhere to the contact surfaces. It also has highdielectric characteristics, and also physical properties extremelydesirable for such use. Its boiling point is above 350 Fahrenheit, sothat it will remain in a liquid stage under normal operation, and itsfreezing point is below zero Fahrenheit. Furthermore, uponvolatilization, it gives off hydrogen and provides for gas quenching atthe contacts. In addition, due to the vaporization under arcingcharacteristics at the relay, the conversion of the liquid into the gasform produces a marked cooling effect, allowing the relay to operate ata cool temperature approximating room condition.

This synthetic liquid, by reason of its viscous vacuum action, maintainsthe two contacts in adherence when the relay is closed, thus tending toovercome the tendency for them to iiy apart should an airplane drop orchange direction suddenly. Furthermore, it prevents premature contact orflashing across due to the fact that the two bodies must press againstthe liquid and displace it before they can contact. Thus, coating ofeither one or both of the contact members with this liquid is desirablesince it requires a rm closure of the relay in order to squeeze out theinsulating liquid and gives a no-arc complete contact. When the contactsstart to spread apart, they have to overcome the viscous character ofthe liquid, and practically no arc can start under the liquid layer.

In applying the use of this liquid to the relays of the presentinvention, I propose a contact structure in which the liquid can be fedto the contact surfaces by means of a wick fed from a liquid reservoiror from any other suitable source, or by providing liquid pockets in thecontact with a hooded arrangement to confine the gases arising uponheating so that the contacts will be bathed in the liquid and itsassociated quenching gas.

Under extreme conditions of temperature, it may be desirable that theliquid be heated to maintain it in a fluid condition, and the presentinvention contemplates also an automatic control means responsive onlyto temperature or pressure for electrically heating the liquid undersuch extremely low temperatures. Similarly, if the relay is of the highcycling type, it may be necessary to maintain the liquid cool in orderto prevent its rapid vaporization, and I also contemplate in the presentinvention the provision of means for circulating either water or arefrigerant liquid through the contact to maintain the same at theproper operating temperature.

The use of such a liquid prevents any plating or possible welding of thecontacts shut, and has the advantage that, upon volatilization, the heatproduced is dissipated rapidly to the walls of the envelope so that nolocalized hot spots can be developed within the relay.

It is also an object of the present invention to provide an open contactswitch of the non-enclosed type, in which the contacts are arranged,with this synthetic liquid being fed to them in any one of a number ofways, certain examples of which will be described in detail hereinafter,and being either cooled or heated, as circumstances may require, tomaintain the liquid at its best op- @rating condition. In suchconnection, it may be desirable to hood one of the contacts with aninsulating ceramic or shielding member which will confine the vapors sothat they are retained around the contact surfaces. Also, the contactsmay be provided with radial channels to insure delivery of the arcquenching liquid to all surfaces of the contacts. The heating orcooling, of course, is provided as has been described in connection withthe enclosed type of relay.

A further object of the present invention is to provide an enclosed typeof relay structure, which may employ an operating coil removed from themetal relay envelope, this solenoid coil being capable of operating aplunger extending through the envelope for operating switch contactstherein. Such a construction is extremely desirable to prevent prematureclosing or opening of the contacts caused by shock or sudden turns, andalso allows the envelope to be made of any desired metal not necessarilynonmagnetic.

In connection with the enclosed type relay, I

LUU.

LLI'JJI IMI I l- DIIHJUI l may provide for the relay actuating coil tobe disposed within the metal envelope, in which case the envelope neednot be of non-magnetic material, or the actuating coil may surround theenvelope, as disclosed in my previous application, Serial No. 373,597,filed January 8, 1941, or as shown in Hedin application, Serial No.311,915, filed December 30, 1939, in which the magnetic coil surroundsthe envelope, and the envelope must then be of non-magnetic material,such as austenitic steel or the like.

With the open contact unenclosed type of relay, it is of course arelatively simple problem to feed the synthetic quenching liquid to thecontact surfaces. However, in the enclosed type of relay, this may bedone through a reservoir which carries an appreciable supply of theliquid, or the reservoir may be arranged for access from the exterior ofthe envelope to rell the same, in which case, suitable means is providedfor reheatng the interior of the envelope to drive out any air that mayhave been admitted during the filling operation, since normally theenvelopes are evacuated and filled through a tubulation which is thensealed off.

It is apparent that the present invention contemplates a wide range ofconstructional details insofar as the arrangement of the envelope andthe sealing means therefor is concerned, as well as the type andarrangement of the relay within the envelope and the various contactarrangements for such a relay. While the present description showscertain embodiments and designs which I have found advisable, it is byno means to be considered as limited to such forms, but only asillustrative of some ways in which the invention may be embodied.

Other objects and advantages of the constructions herein disclosed willbecome more apparent to those skilled in the art from the followingdetailed description which, taken in conjunction with the accompanyingdrawings, discloses the construction and operation of preferred forms ofthe present invention.

In the drawings:

Figure 1 is a sectional view through one iorm of enclosed relayembodying the present invention;

Figure 2 illustrates the manner in which the synthetic quenching liquidcan be heated to maintain it at the desired operating temperature.

Figure 3 is a sectional view through a modified form of construction, inwhich the relay coil is disposed exteriorly of the envelope;

Figure 4 is a sectional view disclosing another form of enclosed relaystructure embodying the use of a cup-shaped member which contains thearc-quenching liquid, which may be heated externally;

Figure 5 is a sectional view showing a modied contact arrangement, whichmay be used either with an enclosed or open air type relay;

Figure 6 is a corresponding view of another modified contactconstruction;

Figure 7 is a sectional view of a still further modification of thecontact structure;

Figure 8 illustrates a contact structure in which the synthetic liquidmay be replaced through the medium of an oil can or the like;

Figure 9 is a sectional view of an open well type contact structure;

Figure 10 is a view of a. relay contact structure embodying means forcooling the liquid at the contacts;

Figure 11 is a sectional view of a further modil I I fication of theenclosed type relay structure; and

Figure 12 is a sectional view of a still further modified enclosedswitch arrangement.

Referring now in detail to Figure 1, there is shown in this form of theinvention a metallic shell or envelope 5 which may be cup-shaped ingeneral form having the enlarged end portion 6. Seated Within this endportion against the shoulder 'I is an insulating bushing 8 which may bea ceramic or hard rubber, or other substantially non-resilientinsulating material. Mounted on the inner face of the bushing 8 is thebracket member 9 carrying a relay coil I0 surrounding an armature I2.Pivotally mounted on one end I3 of the bracket is the armature arm I4carrying the contact member I5 at the end thereof and normally held awayfrom the core I2 by means of the spring I8. The relay structure described may be considered as any standard type of relay, or may be arelay of special design, but it will be noted that it is entirelydisposed within the envelope and is sealed thereby from the atmosphere.

Backing up the bushing 8 is a resilient gasket member or sealing meansI1, which has an an.- nular ange or skirt I8 disposed within a suitablerecess portion of the bushing to provide a greater length of seal alongthe internal wall of the envelope. The gasket Il is compressed inposition by means of a disc-like compression member I9, which may behard rubber, ceramic or the like, and the compression member I9 islocked in compressed position by means of the retaining washer 20 andthe spun-over edge 22 of the envelope. This type of locking arrangementis disclosed and described more clearly in Bear patent, No. 2,251,011,issued July 29, 1941. and provides a Very positive seal for the open endof the envelope. The two terminals for the relay coil I0 are indicatedat 23 and 24, and are provided intermediate their ends with shoulderportions 25 which hold them against axial movement by seating inrecesses formed in the outer face of the bushing 8 being held in suchrecesses and sealed by the resilient gasket I'I. Similarly a second pairof terminal members 25 and 2G extend through the bushing B in a similarmanner. The terminal member 25 is provided at its inner end with a fixedcontact portion 2l to be described in more detail hereinafter. The otherterminal member 26 is connected through the exible pigtail 28 to thearmature contact I5.

.. whereby a circuit is completed between the contacts 25 and 26 whenthe armature core I2 attracts the armature arm I 4 to close the contactsI5 and 21.

The interior of the envelope in which the relay is mounted is preferablyadapted to be evacuated completely, it being understood that theenvelope 5 may be subjected to a hydrogen annealing process, asdescribed in. Uno C. Hedin application, Serial No. 325,154, led March21. 1940, now Patent No. 2,284,899, whereby all occluded gases aredriven out of the pores of the metal and they are lled with hydrogen toprevent any leakage of hydrogen therethrough. After evacuation, theenvelope is lled with dry hydrogen gas under appreciable pressure suchas from 4 to 6 atmospheres, the evacuation and lling being accommodatedby the port 3Il in the closed end of the envelope. which may be providedwith a tubulation or may be sealed over f by means of a plastic sealsuch as the seal 32 after the hydrogen gas under pressure has beenintroduced into the shell.

Mounted on the inner face of the bushing 8 is a receptacle or reservoir33 which is provided with a fill plug 34 extending through the wall ofthe envelope and having suitable gasket means 35 for sealing the same.The reservoir is adapted to contain the liquid previously described,which is used for coating the contacts to prevent cor.- rosion orwelding thereof, and which also prevents any oxidation. Further, thisliquid is of such physical characteristics that it has a tendency toquench any arcing between the relay contacts, and is of sufficientviscosity that it prevents premature flash-over before the two contactscome together, requiring that the force of closing the contacts besufficient to squeeze out the liquid therebetween before the circuit canbe closed. The liquid has a relatively low vaporizing point, about 350F. and the vapor acts as an arc quenching gas to both dissipate heat andto resist arcing. This liquid is preferably an anhydrous alkalineliquid, such as triethanolamine, and is transmitted to the contact 21 bymeans of the wicking 36, which extends into the reservoir 33 and thencethrough the terminal stud 25 into a suitable recess 31 formed in thecontact 21 and communicating with all portions of the contact by reasonof the channels 38. The liquid is transmitted through the wicking to thecontact 21 and acts as a cooling medium as well as an arc quenchingmeans.

Further, due to the hydrogen fill within the envelope, it is apparentthat little or no arcing can take place, since the hydrogen is more than100 times as effective in reducing the sparking potential between thecontacts than air or hydrogen. Consequently, for producing the shrtestarc duration and maximum interrupting ability, the use of hydrogen underappreciable pressure is extremely desirable. The use of hydrogen incontact with the contacts maintains them clean and bright, while the useof the liquid prevents any fusion of the contacts together and alsoserves as a heat dissipating medium since the liquid when vaporizedmoves as a gas, and when it contacts the walls of the envelope itcondenses, thereby dissipating heat throughout the envelope.

It may be desirable to provide the envelope with a suiitable safetypressure device to prevent building up too great a pressure therein,although the seal is capable of withstanding pressures up to two orthree thousad pounds per square inch. I therefore may provide thepressure release valve 40, which normally is closed in the tapered valveseat 42. The valve is normally pressed into sealing engagement in theseat by means of the spring 43, but of course under extreme pressures,will be forced outwardly to allow escape of pressure.

In some cases, such as when operating a relay of this type at highaltitudes, the rarifled atmosphere and consequent low temperature maycause the liquid in the reservoir 33 to congeal, since it passes intothe solid state at a little below the zero degree Fahrenheit. To remedythis condition there is shown in Figure 2 a construction which providesfor maintaining the liquid in the reservoir 33 in a proper condition.This is accomplished by means of a heating coil 45 which is connected toan electric circuit through conductors 46 and 41. A suitable thermostat48 controls the operation of the circuit. and produces a heating of theliquid whenever the temperature gets to a point where there ispossibility of congealing of the same.

In Figures 5 to 9, inclusive, there is disclosed a number of othercontact arrangements which may be provided for switches or relays ofthis type whether they are operated within an envelope or in open air.For example, the construction shown in Figures 5 and 6 are especiallyadvantageous for open air operation where it is desired that thecontacts be prevented from pitting or from fusing or from oxidation.

Considering Figure 5, the relay arm 50 in this construction is providedwith the contact arm 52 carrying the contact 53. This contact isprovided with a ceramic enclosing hood 54 open at the bottom. Disposedwithin the confines of the hood is the fixed contact 56 mounted on theterminal stud 51. A suitable liquid reservoir 58 is provided which islled, as indicated at 59, with the alkaline liquid. A suitable wicking60 transfers the liquid up through the terminal post 51 to the contact56, the contact 56 being provided with radial channels 58 and a centralrecess 59 in which the wicking terminates. It will be apparent that withsuch a construction vaporization of the liquid under rapid cycling ofthe relay will result in the gas being trapped Within the hood 54,thereby flowing over and around the contact surfaces. This vaporizationof course, produces a concurrent cooling, and also bathes all thecontact surfaces with a liquid or gas to maintain them clean and brightand to quench any arcs that might be struck therebetween, as well aspreventing premature flash-overs.

Due to the presence of the gas or liquid over the contact surfaces, itis apparent that as the two contacts move toward each other, there willbe no initial arcing since it is necessary to physically displace theliquid or gas before an air gap is produced, and consequently, no airgap will be produced before the contacts come together. As a result, thesparking potential is materially increased, which results in muchgreater life and more efficient operation of the relay.

The construction shown in Figure 6 is similar except that the contact 53is provided with a vertical extension 62 about which is mounted aheating coil 63. The heating coil 63 transmits heat through the metal ofthe Contact 53', which in turn vaporizes the liquid within the contact56, this vapor being trapped within the hood 54, and consequentlyflowing over and coating the surfaces of the two contacts. Thus, ineffect, a gas filled contact structure is provided even in an open aircontact relay, and since the liquid, upon vaporization, produces a gasrich in hydrogen, it is apparent that a hydrogen atmosphere is producedabout the contacts, which materially increases the resistance tosparking or arcing, and thus prevents any possible fusion or corrosionof the contacts.

Figure 7 discloses a simplified form of contact structure in which themovable contact 65 is adapted to engage a fixed contact 66 which isrecessed and provided with a packing or wicking 61 saturated with theliquid. A portion of this wicking may project a slight distance abovethe surface of the contact 66 so as to provide for wetting of thiscontact surface with the liquid. This provides a pressure head resistingengagement of the contacts until they have displaced this liquid,thereby preventing any premature arcing or flash-overs. The liquid inthe contact 66 may be renewed, as required, by means of an oil can orany other suitable means of introducing the liquid into the recess.

In Figure 8 a pair of vertical contacts are disclosed, the movablecontact 10 being adapted to move toward and away from the fixed contact12. The xed contact 12 is recessed as at 13 to provide a channel for theliquid, which, because of its viscous nature, will stay within thepassageway 13, and will vaporize at the base of the contact 12 toprovide the gas essential to prevent arcing at the contacts. The liquidmay be reneWed either by a wicking introduced into the open end of therecess 13, or by means of an oil can or any similar means.

The construction in Figure 9 shows a pair of contacts having matingcontact surfaces, the movable contact 1-5 having a projection or boss 16adapted to extend into a well or recess 11 in the xed contact 18. Thiswell or recess is filled with the liquid, and the liquid is displacedover the contact surface and partially vaporized by the heat producedbetween the contacts to provide a gaseous atmosphere of hydrogen aboutthe contacts during operation of the relay.

Thus it will be seen that in all of these various types of contactstructures the liquid is brought into close proximity to the contactsurfaces, and is so arranged that it can be readily vaporized by theheat of contact to provide the gaseous hydrogen atmosphere about thecontacts during operation of the relay.

Considering now the construction shown in Figure 3, this construction isparticularly desirable for fast operating airplanes in which rapid turnsand changes of direction would, through the influence of gravity andcentrifugal force, cause possible misoperation of a normal type relay.

In this form of the invention, the metal envelope 85 comprises acup-shaped shell having the bushing 86 seated in the open end thereof,the bushing being provided with an axial bore through which extends abrass or austenitic steel sleeve 81. This may be a stainless steelsleeve or any non-magnetic material. At its inner end, the sleeve 81 isprovided with a contact disc 88 which may be coin silver or any otherapproved contact material.

The sleeve 81 is provided with a shouldered portion 89 seating in acorresponding recess in the bushing 86 and held in position by means ofthe resilient gasket 90, which in turn is compressed in position by therigid compression member 92. The compression member 92 is locked inposition by the spun over end 93 of the envelope 85, and is providedwith a reduced cylindrical extension 94 forming an abutment againstwhich the magnetic actuating coil 95 is disposed within its casing 96.The coil 95 is provided with the two conductors 91 and 98 which connectit, to a suitable circuit for energization. The end of the sleeve isclosed, and is provided with a tubulation 99 which, through the hollowbore |00 in the sleeve, is capable of being used for evacuating theenvelope 85 and filling the same with hydrogen under pressure. Mountedwithin the bore of the sleeve 81 is a Bakelite sleeve |02 forming aguide for the reciprocating plunger |03. This plunger is normallypressed inwardly toward the closed end of the envelope 85 by means of aspring |04 seated in the outer end of the sleeve 81. The plunger |03 isformed of magnetic material such as iron, and carries at its inner end aresilient contact member which, through the resilient connection |06, iselectrically connected to the shell 85, a suitable conductor |01 formingone side of the circuit controlled by the contacts 88 and |05. Theopposite side of the circuit ls connected from the contact 88 throughthe sleeve 81 and the tubulation 99 to a conductor |08.

In the operation of this construction, the actuation of the coil resultsin the plunger |03 being drawn to the left, as viewed in Figure 3,closing the contacts and completing the circuit between the conductors|01 and |08. Upon release of the magnetic action of the coil 95, thespring |04 abruptly moves the plunger |03 inwardly, breaking thecontact. The use of the hydrogen gas within the envelope of courseprotects these contacts against deterioration.

The construction shown in Figure 4 involves a relay of the same generaltype as shown in Figure 1, except that it is mounted in invertedposition and has a somewhat different means for introducing the liquidin vapor form around the contact surfaces. The same reference numeralshowever will be used to indicate corresponding parts.

However, the contact 21' in this form of the invention is not recessed,and has no direct connection to any source of liquid supply. Mounted inthe closed end of the envelope 5 which is at the bottom of thestructure, there is provided a cup-shaped insulating retaining member||0, which may be formed of asbestos or the like, and which is adaptedto contain the liquid ||2. Surrounding the outer portion of the envelopeadjacent this end is a fiber insulating cap which carries on its surfacethe electrical heating coil ||3, which applies heat through the metal tothe liquid within the cup ||0, vaporizing this liquid and causing it torise upwardly into proximity to the contacts |5 and 21. As the liquidcontacts the cooler walls of the envelope, it condenses and drips backdownwardly, as indicated at |i4. This provides, in addition to thehydrogen gas under pressure sealed within the envelope by means of thetubulation ||5, a circulating gaseous medium, which has excellent arcquenching, heat dissipating and lubricating characteristics. Thisprovides very eliicient protection of the surfaces against anypossibility of damage by arcing or flash-overs, and together with thehydrogen gas, insures that the contacts will always remain clean andbright.

Considering Figure 10 in detail, in this construction there is shown acontact arrangement somewhat similar to that shown in Figures 5 and 6.However, the xed contact terminal post |20 in this form of the inventionis provided with an end recess |22 to which extends an inlet conduit |23and an outlet conduit |24. The contact |25 mounted on the post |20 isprovided with ports |28 communicating with the recess |22.

By the use of this construction, the liquid can be circulated throughthe contact arrangement, and can be maintained cool so that it will notvaporize too rapidly, and due to its viscosity it will not be forcedoutwardly through the ports |26 in too rapid a manner, but will vaporizeand maintain the contacts cool even when the relay is of the highcycling type. This provides a continuous flow of the liquid to thecontacts, and lnsures that they will always be surrounded by thedesirable gaseous hydrogen atmosphere. The conduits |23 and |24 may beconnected to a cooling system or to a heat exchanger, as desired.

In Figure 1l I have shown a modied construction in which the metalenvelope |30, which may be of iron, or 18-8 stainless steel, is coatedover its entire outer surface with thiokol, as indicated at 3|. Withinthe envelope there is disposed a relay structure comprising the armaturearm |32, the contacts |33 and the energizing coil |34. This relaystructure is supported by means of the bracket |35 upon a Bakelite orequivalent gasket member |36 seated against the shoulder |31 formed inthe envelope.

A suitable resilient gasket |38 seals the insulator |36 in position, andis compressed by means of an intermediate compression member |30. Toprovide additional sealing, a second resilient gasket |40 is providedformed of 50% thiokol and 50% neoprene. Against this gasket is disposeda Bakelite gasket |42, which is held in position by means of a retainingwasher |43 pressed in position by the inner flanged lip |44 of a capmember |45 threaded over the outer end of the shell. The cap member |45is provided With radial openings |46 adapted t0 receive a Wrench or thelike for tightening it over the end of the shell to provide the desiredcompression of the gaskets. Within the interior of the envelope there isprovided a coating of polyvinyl alcohol, or the equivalent, which isshown as forming a lining |41 about the interior of the shell and overthe inner face of the bushing |36. This material is also painted overthe gaskets and on the inside and outside surfaces of the syntheticrubber to close the pores against the escape of hydrogen. Preferably,the gasket |38 is of pure gum rubber to retain a resilient pressure onthe gasket |36. The joint between the gasket |36 and shoulder |31 of theenvelope is also coated with polyvinyl alcohol before assembly. Thiscoating is impervious to the passage of hydrogen, and consequently allhydrogen introduced to the envelope through the tubulation |49 is lockedtherein against escape. If desired. the interior of the envelope may beevacuated and filled through the tubulation |50, which also serves asone of the terminal studs extending into the envelope. The otherterminal stud is indicated at |52, and it is understood that four suchterminals are provided, two for the actuating coil and two for the pairsof contacts,

In the construction shown in Figure 11, I have also provided means fordisassembling the structure, this comprising a hook |53 which is seatedin the bushing |36. By engaging the hook after the cap |45 has beenremoved, the entire inner assembly of the shell can be removed if it isdesired to inspect the contacts or to replace the relay, and it isunderstood that the coating material may again be applied after suchremoval before the new assembly is introduced into position.

In the structure shown in Figure 12, I have disclosed a metal envelopeor shell |60 having the shoulder |62 providing an abutment for the rigidinsulating bushing |63. The remaining gasket structure is similar tothat described in connection with Figure 11, and may be coated in thesame manner as described in connection therewith.

Mounted within the envelope in any suitable manner is a motor generatorset, indicated at |64 and |65, respectively, which, being placed withinthe envelope which is sealed and iilled with hydrogen under pressure,allows a higher voltage commutation, and thus can be used with arelatively small motor generator set for generating D. C. current foraviation purposes. The interior of the envelope and the gaskets arecoated with a liquid wax or with the polyvinyl alcohol, as indicated at|66, to seal the same against the escape of any hydrogen by closing thepores of the metal and the pores of the gasket material. This' isprovided by painting the same with the alcohol or by coating the samewith the wax and baking it for a period of approximately one minute at200 to 250 degrees Fahrenheit.

The use of an enclosed envelope with a hydrogen atmosphere underpressure therein for a motor generator set, such as indicated in Figure12, is highly desirable. Hydrogen has the characteristic of both coolingand keeping clean those places in such a set which are inaccessible,while the cooling characteristics of the gas convey the heat to thesurrounding outside jacket and to the large body of surrounding hydrogento dissipate the same, thereby eliminating hot spots. The coils of thearmature rotating in their orbit tend to create isolated hot spots, andthe presence of the hydrogen gas at these coils materially reduces theirtendency to overheat. The higher the pressure of the gas, the greater isthe quenching action on the parts of the motor generator set.

This provide an effective control of temperature under these adverseconditions without employing outside air currents with their possibledust and other contaminations. A motor generator set does not have thecommutation limitations found in open air work when enclosed in thismanner. Further, there would be no tendency of one segment bar to fuseacross to the next, and the surface heat of the brush to the bar causedby oxidation of the surfaces would be eliminated.

It will be apparent that in all of the constructions shown, the use ofeither hydrogen or a synthetic liquid, such as triethanolamine or thelike which produces a hydrogen atmosphere upon vaporization, providesfor protection of the contact surfaces, whether operating in air orwithin an enclosure permitting much greater capacity in the relayswithout any danger of arcing or corrosion of the contacts. The variousmethods for maintaining the liquid in proper operating condition at thecontact surfaces and for preventing the escape of the hydrogen which isunder pressure in the envelope serve to add long life and furtherenhance the operating characteristics of the structures.

I am aware that various changes may be made in certain details of thepresent construction, and therefore do not intend to be limited exceptas defined by the scope and spirit of the appended claims.

I claim:

1. A relay construction comprising a sealed metal envelope, a relayassembly supported in said envelope having a pair of magneticallycontrolled cooperating contacts, a illling of hydrogen gas underpressure in said envelope, a body of an anhydrous alkaline liquid withinsaid envelope, and means within said envelope for conducting said liquidto the surface of at least one of said contacts.

2. The construction of claim 1 further characterized in the provision ofmeans located externally of said envelope and connected to said body ofliquid for maintaining said liquid at a predetermined temperature insaid envelope regardless of ambient temperature variations.

3. The construction of claim 1 wherein said liquid comprisestriethanolamine.

4. The construction of claim 1 including a liquid reservoir in saidenvelope, and iill plug means accessible from outside of said envelopefor reuuvl Hull l- UIHUUII plenishing said liquid from the exterior ofsaid envelope.

5. In combination, a relay structure including a fixed contact and acontact movable into engagement therewith, said fixed contact having a.series of lateral outlet ports below the face thereof provided with acommon inlet port, reservoir means separated from said contacts andcontaining an arc quenching liquid, means for conducting saidliquid tosaid inlet port, said liquid being capable of volatilizing upon heatingof said contact to release hydrogen-rich gas, and hood means cariied byand movable with said other contact and extending downwardly below saidports when said contacts are engaged ior confining said gas about saidcontacts.

6. The combination of claim further characterized in means formaintaining said liquid at a predetermined temperature.

7. The combination of claim 5 including a circulating system for coolingsaid liquid connected through said one contact.

8. The combination of claim 5 including means for heating said liquid tomaintain its viscosity substantially constant under varying ambienttemperatures.

9. In combination, a cup-shaped metal envelope, a rigid insulatingbushing in one end thereof supporting a pair of cooperating contactswithin said envelope, resilient gasket means sealing said bushing insaid envelope, a hydrogen gas under pressure in said envelope, andinsulating means coating the interior of said envelope and said bushingand gasket means to close the pores thereof against escape of said gas.

10. The combination of claim 9 wherein said coating means comprises awax applied in liquid form and baked on under application of heat.

11. The combination of claim 9 wherein said coating means comprisespolyvinyl alcohol.

12. The combination of claim 9 wherein said gasket means comprises afirst sealing member of pure gum rubber, an intermediate rigidinsulating disc, and a second sealing member formed of thiokol andneoprene in substantially equal proportions, said last-named sealingmeans being impervious to the passage of gas therethrough.

13. In combination, a cup-shaped metal envelope. an insulating insertseated in one end thereof, a normal open air contact type relay rigidlysupported in said envelope by said insert, resilient gasket meanssealing the end of said envelope against escape of gas, a filling ofhydrogen gas under pressure in said envelope, a reservoir in saidenvelope containing a volatile arcquenching liquid and capable whenvolatilized of giving oir hydrogen gas, an insulating cap over the endof said envelope adjacent said reservoir, and heating means carried bysaid cap for volatilizing said liquid.

14. In combination, a cup-shaped metal envelope, an insulating insertseated in one end thereof, a normal open air contact type relay rigidlysupported in said envelope by said insert, resilient gasket meanssealing the end of said envelope against escape of gas, a filling ofhydrogen gas under pressure in said envelope, a reservoir in saidenvelope containing a volatile arcquenching liquid and capable whenvolatilized of giving oif hydrogen gas, means for conducting liquid fromsaid reservoir to said contact, and lateral ports in said contactadjacent the face thereof providing for escape of said volatilized gasupon heating of said contact by arcing.

l5. In combination, a relay construction including a pair of cooperatingcontacts, one of said contacts having a cavity therein adapted tocontain an arc-quenching liquid, and the other of said contacts having aprojection extending into said cavity when said contacts are closed fordisplacing said liquid over the surfaces of said contacts.

16. In combination, a metal cup-shaped envelope having an enlargedexternally threaded open end, an insulating insert in said end, a relaystructure supported within said envelope by said ceramic, the interiorof said envelope and said insert being coated with an impervious layerof insulating material, resilient gasket means also coated with saidinsulating material disposed in the end of said envelope against saidinsert, rigid compression means engaging the outer face of said gasketmeans, and a cap member threaded over the end of said member and havingan annular axially projecting shoulder engaging said compression meanswithin the end of said envelope for holding said gasket means incompressed position.

1'7. In combination, a tubular cup-shaped metallic envelope,electrically operated means rigidly supported within said envelopeincluding contacts, means for sealing the open end of said envelope.hydrogen gas under pressure in said envelope for quenching arcs at saidcontacts and preventing oxidation thereof, and means comprising a layerof insulating material impervious to the passage of hydrogentherethrough coating the interior of said envelope and said sealingmeans.

HERBERT E. BUCKLEN, JR.

